2 Renmark to border LAP area assessment - EPA - Sa.gov.au

River Murray and Lower Lakes catchment risk assessment for water quality: Results and management options
6 Mannum to Wellington LAP area assessment
6.1 Description of the area
The Mannum to Wellington Local Action Planning (MW LAP) area covers approximately 84 km of the River
Murray from Mannum township to the point south of Wellington where the river enters Lake Alexandrina
(Figure 6.1). The area incorporates the boundaries of the Mid Murray, Rural City of Murray Bridge and
Coorong District councils with the major towns in the region being Mannum, Murray Bridge and Tailem
Bend.
The extensive recreational zones in the MW LAP area include several houseboat rental marinas and shack
areas, popular skiing and boating regions, and numerous informal (no facilities) and formal camping
grounds. The townships, in particular Murray Bridge, support extensive industrial and rural land uses (eg
abattoirs, piggeries and milk processing plants). Flood-irrigated dairy pastures are a prominent land use
on the river’s reclaimed floodplain. The area also has several small local and major metropolitan raw
water supply off-takes (eg Mannum–Adelaide pipeline, the Murray Bridge-Onkaparinga pipeline and the
Tailem Bend-Keith pipeline).
The MW LAP area plan (MW LAP 1999) details several strategies and actions aimed at:
• a local community committed to achieving sustainable local uses of the River Murray
• improved River Murray water quality
• sustainable irrigation
• improved ecological health of the local River Murray floodplain and wetland.
At the water quality monitoring sites at Mannum, Murray Bridge and Tailem Bend, testing is carried out
regularly on a wide range of water quality parameters. The monitoring results show that the region is an
area of declining water quality, particularly for indicator bacteria (E coli) and nutrient levels (EPA
2001a). The decline in water quality has been largely attributed to drainage water discharges from floodirrigated
dairy farms operating in the area (EPA 2001a). Significant rehabilitation programs are currently
being implemented on flood irrigation areas within the Lower Murray to address this issue.
Total heavy metals at the monitoring stations in this area were generally at a low level but there was a
significant increase in iron levels at Murray Bridge, the cause of which is uncertain. Pesticide levels were
generally at, or below, detection levels. ‘Run of the river’ salinity data collected by DWLBC indicates the
saline groundwater inputs entering the river in this area are lower than in the Riverland.
Turbidity levels in the river are elevated from where the river enters South Australia to the mouth,
significantly influenced by contributions from the Darling River (which has a high clay colloid level) and
flood events (MDBC 1988). The slight drop in turbidity from Murray Bridge to Tailem Bend may be
associated with low flow in this area and thus settling of particulate material (SA Water unpublished data).
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